As electronic equipment, especially portable electronic equipment such as cellular phones and portable information terminals, is becoming smaller in size and more sophisticated in function rapidly, various types of semiconductor chips are advancing toward smaller sizes, lower profiles, and higher integration. For cellular phones, memory-type portable music players, HDTV video cameras, 3D game consoles, and the like, memories of even higher capacities and smaller sizes and high density packaging of bare chips are demanded. Among known technologies to meet these demands is to mount bare chips in a laminated state at high density in the fields of SIP, MCM, CSP, PC cards, SD cards, and the like (for example patent documents 1 to 4). Patent documents 1 and 2 disclose technologies for joining single-side or double-side mounted rigid substrates to each other with solder balls for lamination, and attaching the same to a motherboard. Patent document 3 discloses a PC card in which a flexible film substrate having bare chips mounted on both sides alternately is folded back 180° at each interval between the mounting areas of the bare chips for lamination, and is attached in a symmetrical mounting mode so as to cover both the surface and backside of a PC card board and built into a PC card case. Patent document 4 discloses a semiconductor apparatus in which a film substrate having bare chips mounted on both sides alternately is folded back 180° at each interval between the mounting areas of the bare chips for lamination, and all the bare chips are wrapped in.
[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-68443
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-356138
[Patent Document 3] Japanese Patent Laid-Open Publication No. Hei 11-282995
[Patent Document 4] Japanese Patent Laid-Open Publication No. 2000-12606